Peridicarboxylic acid imide dyestuffs containing at least one isothiocyanate group



3 045,019 PERIDICARBOXYLIC A(Jm lMIDE DYESTUFFS CONTAINING AT LEAST ONE ISOTHIOCYA- NATE GROUP Hans Heinrich Bosshard and Heinrich Zollinger, Basel,

Switzerland, assignors to Ciba Limited, Basel, Switzerland, a Swiss firm No Drawing. Original application May 4, 15959, Ser. No. 812,574. Divided and this application June 21, 1960, Ser. No. 43,972 Claims priority, application Switzerland May 6, 195$ 2 Claims. (Cl. 260-281) This invention provides valuable new peridicarboxylic acid imide dyestuffs, which contain at least one acid group imparting solubility in water and at least on isothiocyanate group.

As acid groups imparting solubility in water there may be mentioned carboxylic acid groups and especially sulfonic acid groups. The isocyanate group or groups are advantageously aromatically bound.

The invention also provides a process for the manufacture of the aforesaid new dyestuffs, wherein a peridicarboxylic acid irnide dystufr', which contains at least one acid group imparting solubility in water and at least one primary amino group, is treated to convert the primary amino group into an isothiocyanate group, for example, by reaction with thiophosgene.

As peridicarboxylic acid imide dyestuffs there are to be understood compounds which contain the grouping of the formula in which R stands for a hydrogen atom, an alkyl or aryl V group. Of particular interest as starting materials are the perylene-tetracarboxylic acid imides of the formula OO O O in which R stands for a benzene radical which contains at least one sulfonic acid group and a primary amino group.

The conversion of the amino group into the isothiocyanate group by the reaction One molecular proportion of thiophosgene is required for each primary amino group entering into reaction. However, it is of advantage to use a small excess, for example, about 10%, of thiophosgene. The reaction takes place at room temperature, but it is of advantage to heat the reaction mixture, advantageously at a temperature not exceeding 60 C. The isothiocyanate formed is advantageously precipitated from the reaction medium by the addition of a water-soluble inorganic salt, especially sodium chloride or sodium sulfate. The conversion of the amino group into the isothiocyanate group can also be carried out by reacting the amine with carbon disulfide in the presence of an alkali metal hydroxide, ammonia or an amine to form the dithiocar- 'bamate, for example, according to the reaction R-NH2 OS? 0H RNHCS-S Hi0 dithiocarbamate The dithiocarbamate can be converted into the isothiocyanate by reaction with phosgene or sodium hypochlorite according to the equation dium in which they are formed and, notwithstanding the presence of reactive groups, worked up into useful dry dyestuif preparations. The dyestuffs are advantageously isolated by filtration. The filtered dyestuffs may be dried,

if desired, after the addition of a neutral or weakly alkaline extender. The drying is preferably carried out at not too high a temperature, that is to say, not higher than 50 C., and, if desired, under reduced pressure. The new dyestutfs are suitable for dyeing or printing a very wide variety of materials, such as animal fibers, for example, wool, or synthetic fibers, for example, nylon or polyvinyl alcohol fibers, and especially materials of natural or regenerated cellulose.

A, For this purpose it is of advantage to use aqueous solutions of the dyestuffs. These solutions advantageously contain a more or less neutral and preferably inorganic salt, such as an alkali metal chloride or sulfate, and if desired, an advantageously inorganic acid-binding agent, such as an alkali metal carbonate, alkali metal phosphate, alkali metal vborate or perborate, or a mixture thereof, and especially a buffer mixture of such agents, and are used for dyeing in the cold or at a moderately raised temperature, or if a higher temperature, for example, at 6080 C., if no alkali is present. During the dyeing process the isothiocyanate groups react with the poly-c hydroxylated material to be dyed, so that the dyestuil probably enters into chemical combination with the fiber. a

In an advantageous form of the dyeing process the material to be dyed is impregnated at room temperature or a moderately raised temperature with an aqueous solution of the dyestutf, advantageously in the presence of an alkali or an agent yielding an alkali, such as sodium carbonate, and then the impregnated material is subjected to a heat treatment, advantageously in air at a temperature above C. or in steam at 100 C. The impregnation may be carried out by the direct dyeing method or by printing or by the so-called pad dyeing method. Those dyestufis of this invention which contain no. groups imparting solubility in water can be used, for example, as pigments or can be condensed with hydroxylated compounds in the absence of water to form coloured artificial materials.

The present application is a division of copending application, Serial No. 812,574, filed May 4, 1959.

The following example illustrates the invention, the parts and percentages being by weight:

Example 1 2 parts of the dyestufi of the formula are dissolved as disodium salt in 200 parts of water at the boil. After cooling, the dyestutf solution is added slowly and with stirring at 20 C. to a mixture of 1 part of thiophosgene in 30 parts of water. The mixture is heated within one hour to 40 C. and maintained at that temperature for 6 hours. The hydrochloric acid liberated is neutralized by the addition of sodium carbonate at intervals. The reaction product is precipitated SOsH NOS

SOJH

with sodium chloride, filtered, washed with acetone and dried on the filter by aspiration of air. When material is dyed as described in the following paragraph, a strong, bluish-red dyeing of good fastness to washing is obtained.

1 part of the dyestuff obtained as described in the preceding paragraph is dissolved in 2000 parts of water at 50 C. After adding 10 parts by volume of sodium hydroxide solution of 30% strength and 6 parts of sodium SOJH 2. The dyestutf of the formula References Cited in the file of this patent UNITED STATES PATENTS Haddock Oct. 22, 1946 OTHER REFERENCES Karrer: Organic Chemistry, 2nd ed., pp. 225-7 

1. A PERIDICARBOXYLIC ACID DIIMIDE DYESTUFF OF THE FORMULA 